COGS 100 Week 7 Lecture 2
Language of Thoughts con't
Importance of physical symbol system hypothesis:
•Intelligent behaviour <=> PSS
•Main characteristic: are physical, can be represented in world, expressed outside of ourselves
•Have both physical and abstract aspect - the meaning assigned to those symbols
•Symbolic patterns stand for physical structures
•Patterns are manipulated by algorithms - results in different patterns
•Relates to problem solving: move from initial state to goal state; particular algorithms solve certain
•Universal can read any PSS (true ones)?
•Problem: Chinese Room Experiment - does it truly UNDERSTAND symbols? Knows syntax, not
•Symbol grounding problem - how meaning is assigned to symbol
Lang of thought - Fodor:
•Resemble formal, logical languages
•Use to think, perform operations
•All hear same thing, all hear "Cat" but hear it in a different way (polymorphism)
•Beliefs and desires, fears, hopes are physical symbols, objects, patterns, cause us to behave in a certain
•Ex: I am thirsty. That is a physical symbol. Changed to a desire to drink. Causes me to go get a glass of
•Propositional attitudes (these things) have shape
•Syntax as a form - how get from that to meaning? How is it mapped? How does meaning result in action?
•Lang of thought functions just like a Turning machine or any other PSS
•Symbols, processed represented by symbols, carried out on symbols
•Operate exclusively algorithmically - cares about semantics, but also does not
•Rules expressed symbolically
•Logical terms I don't remember and syllogism!
•True conclusion if conclusion is output of premise: if p -> q, p, q
•That is validity - is the form. Are formal steps to follow from instructions.
•Semantics -> about truth of argument. Argument can be valid but not true.
•Language of thought needs to follow these principles.
•Operations must respect rules of syntax, but also rules of meaning
•If p, q you have p^q
•Existential quantifiers •Get transformed by certain rules, rules must obey